Question

我尝试创建一些代码以将新的注册用户写入CSV文件。它正在替换文件中的现有用户。现在，它没有输入任何数据。我不确定哪里出了问题。

这是代码：

FirstName = input("Enter your  first name: ")
Surname = input("Enter your surname: ")
Age = input("Enter your age: ")
YearGroup = input("Enter your year group: ")
userName = input("Create a unique username: ")
passWord = input("Create a password: ")
fieldnames =['Username', 'Surname', 'First Name', 'Age', 'YearGroup', 'passWord']
reG = [{'Username': userName, 'Surname': Surname, 'First Name': FirstName,
                    'Age': Age, 'YearGroup': YearGroup, 'passWord': passWord}]
with open('StudentUserName.csv', 'w', newline='\n') as csvUser:
    reG = [{'Username': userName, 'Surname': Surname, 'First Name': FirstName,
                    'Age': Age, 'YearGroup': YearGroup, 'passWord': passWord}]
    writer = csv.DictWriter(csvUser, fieldnames)
    #writer.seek(0,2)
    writer.writeheader()
    writer.writerow(reG)

    #writer.writerow("\r")
    #writer.writerow({userName, Surname, FirstName,
    #                 Age, YearGroup, passWord})
csvUser.close()
print ("Registration completed")

Answer 1

您正在使用w（写入模式）打开文件：

以csvUser的身份打开（'StudentUserName.csv'，' w '，newline ='\ n'）：

要添加新行（附加），您需要以附加模式“ a”打开文件。因此将是：

以csvUser的身份打开（'StudentUserName.csv'，' a '，newline ='\ n'）：

可能希望阅读以下内容：https://docs.python.org/3.4/library/fileformats.html

Answer 2

这里有一些调整可以使您的程序按预期工作：

import csv
import os

FirstName = input("Enter your  first name: ")
Surname = input("Enter your surname: ")
Age = input("Enter your age: ")
YearGroup = input("Enter your year group: ")
userName = input("Create a unique username: ")
passWord = input("Create a password: ")

fieldnames = ['Username', 'Surname', 'First Name', 'Age', 'YearGroup', 'passWord']

filename = 'StudentUserName.csv'

# The file is now opened in append mode instead of write mode.
with open(filename, 'a', newline='\n') as csvUser:

    # reG is now a dictionary, as required by writerow.
    reG = {'Username': userName, 'Surname': Surname, 'First Name': FirstName,
           'Age': Age, 'YearGroup': YearGroup, 'passWord': passWord}

    writer = csv.DictWriter(csvUser, fieldnames=fieldnames)

    # if it's an empty file, write the header
    if os.stat(filename).st_size == 0:
        writer.writeheader()

    writer.writerow(reG)

    # writer.writerow("\r")
    # writer.writerow({userName, Surname, FirstName,
    #                 Age, YearGroup, passWord})
csvUser.close()
print ("Registration completed")

该文件现在以附加模式而不是写入模式打开。
reG现在是字典，符合writerow的要求。
仅当文件为空时才添加标题。

在csvFile中写入新行

2 个答案: